The suit, filed in the Tokyo District Court, seeks damages and a permanent injunction against the import and sale of Nanya's DRAMs in the U.S. market.

The suit apparently follows a similar legal action filed late last year. On Dec. 17, 2003, Renesas quietly filed a complaint in the U.S. District Court for Northern District of California against Nanya.

Now, Renesas is going after Nanya in Japan. "Renesas has been attempting in good faith to negotiate a patent license agreement with Nanya," according to the Japanese company. "Despite Renesas Technology's good faith efforts, Nanya has refused to enter into a license agreement for Renesas' patents on terms acceptable to Renesas Technology," the suit said.

"Nevertheless, Nanya continues to willfully import into the United States and to market and/or sell in the United States memory products covered by Renesas' patents. In light of Nanya's actions, Renesas Technology had no choice but to pursue legal remedies in the United States," according to Renesas.